The processing of a silver halide photographic material, e.g., a silver halide color photographic material, in general, comprises a color developing step (i.e., a color forming development step) a desilvering step and an image stabilizing step, e.g., a water washing step, as fundamental steps. In a color developing step, an imagewise dye and a developed silver are formed by the reaction of a color developing agent and a silver salt. In a desilvering step, the developed silver formed in a color developing step is oxidized (bleached) by a bleaching agent having an oxidizing function and becomes a silver salt, and removed from a photosensitive layer together with unused silver halide by a fixing agent which forms a soluble salt. Alternatively, the oxidation to a silver salt and the removal thereof are performed through a single step by means of a blixing solution. An image stabilizing step is a step for adjusting the atmosphere of an image layer for securing the stability of the image formed for a long period of time and comprises washing with water, washing with water and image stabilizing bath, or stabilizing bath substituting for washing.
Each processing step exclusive of water washing is performed using an aqueous solution (called a processing solution) containing one or more processing chemicals. Since each processing solution is relatively in low concentration, it is generally inappropriate in view of economical point, storage space and workability that manufacturers produce processing solutions in a workable state and transport them to a processing laboratory and the processing laboratory stores them.
For coping with this problem, two ways have been conventionally used, i.e., one is a way that processing chemicals constituting a processing solution are prepared in a mixture of powder chemicals compounded in the ratio according to the composition of the processing solution, and the mixture is supplied to a developing laboratory in the form of a packaged solid processing agent, and the solid processing agent is dissolved with water and diluted to appropriate concentration to make a processing solution before use in the developing laboratory, and another is a way that constituting processing chemicals are dissolved in high concentration, packed in a container in the form of a concentrated liquid processing agent and supplied to a developing laboratory, and the concentrated liquid processing agent is diluted with water and the like to a prescribed concentration to make a processing solution before use in the developing laboratory.
Solid processing agents are advantageous in view of transporting cost and storage space but are inconvenient in that they should be dissolved in a developing laboratory, dusts of chemicals are scattered, and chemicals must be mixed uniformly, and disadvantageous in that liquid chemicals must be contained in separate bottles (containers of processing agents) at ordinary temperature and combined with powder chemicals of separate packages respectively.
On the other hand, concentrated liquid processing agents are largely advantageous in that the work of dissolution in a developing laboratory can be omitted but do not come up with solid processing agents in the point of transportation and storage. Thus, solid processing agents and liquid processing agents have both advantages and disadvantages respectively, and no processing agents have been found which satisfy all of economical and environmental sides such as the reduction of the volume of processing agents, the reduction of waste containers, the saving of storage space, and the reduction of transporting costs, and simplicity from working side such as labor saving of the work of preparation of processing solutions, and safety.
In recent years, in the improvement of solid processing agents, although a certain progress has been made such that a method of forming a processing agent in the form of tablets has been disclosed (e.g., Canadian Patent 831,928), but as the development processing agent for use in a developing laboratory, concentrated liquid processing agents are more desired from the easiness of working and the purpose of improving the productivity of development processing. Therefore, it is desired to further enhance the degree of concentration of liquid processing agents and give compactness as solid processing agents to liquid processing agents. However, for stably storing concentrated liquid processing agents and generating no hindrance at use, concentrated liquid processing agents should be a homogeneous solution having saturation solubility or less, hence further thickening of solutions is very difficult.
Concerning concentrated liquid processing agents, pasting of black-and-white development processing solutions has been known for long and pasting of color developers is also conducted for the purpose of concentration and from other various purposes. For example, pasting of a color developer has been tried by using an alginic acid derivative as a thickening imparting agent, i.e., a thickener, and the application techniques to a concentrated liquid processing agent for a color photographic material are also disclosed. However, the pasting of color developers is not to heighten the degree of concentration of the processing chemicals by increasing the solubility but merely to delay precipitation or delay the agglomeration and solidification of insoluble matters even if precipitation occurs. Therefore, although pasting has the effect of prolonging the useful life of processing chemicals a little, it cannot essentially solve the problem to reduce the volume of processing chemicals, hence pasting is not a technique of developing the advantage of liquid processing agents.
The liquid processing agents for a color photographic material consist of a color developer, a bleaching agent and a fixing agent or a blixing agent, and a stabilizing solution. Of these processing agents, a color developer contains a p-phenylenediamine derivative as a developing agent, and since this developing agent is relatively in low concentration, thickening is largely restricted such that the developing agent is liable to precipitate during preservation. In addition, since the developing agent is susceptible to air oxidation, deterioration of the developing agent progresses with the lapse of time during preservation. As a result, the air oxidized developing agent becomes tar-like substance and adheres to the wall of a container, which hinders the reclaim and reuse of the container. Thus the concentrated liquid developer has various problems of the precipitation of the developing agent due to restriction on solubility, the air oxidation of a color developing agent during preservation, and the resulting coloring contamination of a container.
The prevention of precipitation of the color developing agent is disclosed in various patent specifications including JP-A-6-194797 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), e.g., methods of adding N,N-di-substituted aniline derivatives, alkyldiphenyl ether disulfonic acids, anionic surfactants, aromatic sulfonic acids, p-toluenesulfonic acids or alkanolamines alone or in combination are disclosed. Any of these methods certainly shows the precipitation prevention effect but the effect is not sufficient, thus these methods are not the means to essentially solve the problem.
Further, for preventing the air oxidation of the color developing solution, the development of more effective preservatives than hydroxylamine salts conventionally used has been promoted. Dialkylhydroxylamines and hydroxylalkyl-hydrazines having a larger preserving effect are disclosed in JP-A-4-443. The preserving effect has been improved by these preservatives but still further advancement has been required.
As mentioned above, for the improvement of the use aptitude of the concentrated liquid development processing agent, the prevention of precipitation of the color developing agent, i.e., the improvement of the solubility and the storage stability has been strongly desired.
As a means to solve such a kind of problem, it is disclosed in JP-A-11-174643 that ethyleneurea has an excellent precipitation prevention effect of the developing agent in the concentrated liquid development processing agents. Therefore, as such a precipitation preventing agent, the realization of precipitation prevention effect of the same with or more than ethyleneurea is required.
As the above concentrated liquid development processing agent is diluted to prepare a color developing solution or a color developing replenisher and a silver halide color photographic material is color development-processed in a color developing tank, the components of the color developing solution precipitate as color development is continued, which causes a phenomenon that the precipitated crystals of the components of the color developing solution creep over the wall of the developing tank, or the contamination by tar is generated on the wall of the developing tank, followed by the reduction of the processing activity of the color developing solution. The methods to solve these problems are also required.